Jennifer Lawrence is a force, whether as the hero of ”The Hunger Games” or the overburdened, inventive single mother she plays in ”Joy.”

The Oscar winner is in every frame of David O. Russell’s new film, shining even among a star-studded cast with a performance that brings continuity to the writer-director’s ambitious but flawed story about the dogged persistence of a determined entrepreneur.

Lawrence plays the title character, Joy, whose last name is never revealed but who’s based on real-life home-shopping magnate Joy Mangano, creator of the Miracle Mop and an executive producer of the film. Text onscreen at its opening says it is ”inspired by true stories of daring women, one in particular.”

Russell’s eighth feature film (and third collaboration with Lawrence) introduces Joy in the years before she makes herself a millionaire. Working in a meaningless job, she struggles as the financial and emotional center of a dysfunctional, multigenerational family. She lives in a crumbling house with her grandmother (Diane Ladd), her soap-opera obsessed mom (Virginia Madsen), along with her two children and her ex-husband, who lives in the basement.

Flashbacks and daydreams show Joy as a bright, imaginative child who reluctantly followed a more conventional path when family responsibilities took hold. But when a flash of inspiration hits after years of life dissatisfaction, she bets her future on it.

With moral support from her grandmother and ex-husband, seed money from her father’s wealthy girlfriend (Isabella Rossellini), and a glimmer of hope from a QVC executive (Bradley Cooper), Joy stakes everything she has on her new invention: a self-wringing mop with a machine-washable head.

Along the way, she experiences elation and despair, personally and professionally. Lawrence brings all the power and intensity required to portray a devoted mother and fierce businesswoman growing up through her 30s, even if the actress looks sweetly youthful throughout. It’s her fire and range that speaks.

And the 25-year-old star doesn’t take anything away from older actresses, who relish in delicious opportunities of their own. Rossellini, 63, is perfectly cast as an Italian widow, while 80-year-old Ladd glows as a doting grandmother and the film’s narrator. Madsen, 54, melts into her character, a recluse in oversized glasses whose whole world is a TV soap opera starring Susan Lucci.

Lucci, 68, plays a powerful heroine in the fictional soap that’s meant to be analogous to Joy’s journey of self-discovery, but the technique doesn’t really work, especially since the mother’s obsession with the show seems to border on mental illness. Still, it’s great to see Lucci back in her element.

Returning Russell collaborators Robert DeNiro (“Silver Linings Playbook”) and Cooper (“Silver Linings Playbook,” ”American Hustle”) each predictably deliver, even if their characters aren’t well-drawn. At one point, Cooper’s sympathetic home-shopping exec tells Joy he’s too busy to hear her pitch, then goes into a lengthy explanation about the history of QVC, which seems oddly expository. The script suffers from further clunkiness when Joy explains her business plans to her 5-year-old daughter (endearingly played by twins Aundrea and Gia Gadsby).

While Russell had unfettered access to Mangano, he says he took liberties with the facts of her story, creating a fictional half-sister (Elisabeth Rohm) to add drama beyond the despondent mom and codependent dad. It’s hard to know what really happened, but it seems like a woman supporting her family while building a multimillion-dollar fortune with nothing more than ingenuity and determination would be dramatic enough.

Despite the convoluted family dynamics and less-than-successful use of the show-within-a-show trope, Lawrence makes Joy easy to believe and easy to root for, no matter what she’s selling.

”Joy,” a Twentieth Century Fox release, is rated PG-13 by the Motion Picture Association of America for ”brief strong language.” Running time: 124 minutes. Three stars out of four.